Pilocarpine is the most commonly used drug in glaucoma therapy, and in the past it has been assumed to pass through the cornea abundantly. Recent investigations, however, have indicated that only a small fraction of topically administered drug is transported to the aqueous, because of poor epithelial penetration and possibly other intracorneal barriers. The clinical efficacy of pilocarpine is thus limited by transcorneal flux efficiency. The proposed research is a developmental investigation of the use of liposomes (phospholipids vesicles) as vehicles to enhance drug penetration. Preliminary experiments with corneal endothelial monolayers have indicated that the presence of liposomes is associated with increased cell uptake relative to that occurring in free fluid pilocarpine administration. The proposed investigations are designed to elucidate those liposomal characteristics which will maximize cell-vesicle interaction, with the purpose of increasing pilocarpine transport across cell membranes, both in cell culture and the intact cornea. In both, in addition, the metabolic fate of pilocarpine following liposomal administration will be examined, as will the effects of liposomes on the morphology of corneal surface epithelium. The possibility of further enhancing intracellular penetration will be explored by incorporating corneal epithelial cell-specific antisera into liposomal membranes.